Gravity operated electromagnetically controlled gate

ABSTRACT

An electromagnetically controlled, gravity operated gate of simple construction and of reliable performance includes a housing enclosing the principal functional components of the gate assembly. Extending through a wall of the housing is a drive shaft on which is mounted a gate element, the latter including a counterbalanced channel affixed to be rotated by the drive shaft, the channel having affixed thereto a gate arm. Located within the housing is a motor and clutch assembly connected to drive the gear means to which the drive shaft is affixed. Also cooperating with the drive shaft is a follower arm which cooperates with an electromagnet positioned within the housing to maintain the gate arm in a generally horizontal position. Also located within the housing is a switch engageable by the follower arm to maintain the electromagnet energized while the gate is in the horizontal position. A control circuit is provided which in an energized state activates the motor and clutch assembly for moving the gate arm from a vertical to a horizontal position, the switch means being energized by the follower to de-energize the motor, to maintain the electromagnet energized for maintaining the gate arm in the horizontal position. Movement of the gate from the horizontal to the vertical position is achieved by de-energizing the circuit control means so that the gate arm is moved to the vertical position by gravity.

United States Patent McDonald [4 1 Apr. 15, 1975 GRAVITY OPERATEDELECTROMAGNETICALLY CONTROLLED GATE lnventor: Robert R. McDonald, 6028Moss Bank Dr., Palos Verdes Pennisula, Calif. 90274 22] Filed: Mar. 18,1974 [21] Appl. No.: 451,950

[52] US. Cl. 49/334; 49/139; 49/280; 49/335; 49/379 [51] Int. Cl. E0lf13/00; E05f l/OO; E05f 15/10 [58] Field of Search 49/324, 35, 334, 49,349, 49/124, 327, 335, 139, 379, 280; 246/125, 128

[56] Reference? Cited UNITED STATES PATENTS 599,020 2/1898 Small 49/280X 903,905 11/1908 Smith 49/280 X 1,601,783 10/1926 Wallin 49/2801,612,016 12/1926 Harper 49/335 1,663,040 3/1928 Duchshercr..... 49/280X 1,765,178 6/1930 Rick 49/280 X 3,368,305 2/1968 Pickarski 49/35 XPrimary ExaminerPhilip C. Kannan Attorney, Agent, or Firm-George F.Smyth I ix [57] ABSTRACT An electromagnetically controlled, gravityoperated gate of simple construction and of reliable performanceincludes a housing enclosing the principal functional components of thegate assembly. Extending through a wall of the housing is a drive shafton which is mounted a gate element, the latter including acounterbalanced channel affixed to be rotated by the drive shaft, thechannel having affixed thereto a gate arm. Located within the housing isa motor and clutch assembly connected to drive the gear means to whichthe drive shaft is affixed. Also cooperating with the drive shaft is afollower arm which cooperates with an electromagnet positioned withinthe housing to maintain the gate arm in a generally horizontal position.Also located within the housing is a switch engageable by the followerarm to maintain the electromagnet energized while the gate is in thehorizontal position. A control circuit is provided which in an energizedstate activates the motor and clutch assembly for moving the gate armfrom a vertical to a horizontal position, the switch means beingenergized by the follower to de-energize the motor, to maintain theelectromagnet energized for maintaining the gate arm in the horizontalposition. Movement of the gate from the horizontal to the verticalposition is achieved by de-energizing the circuit control means so thatthe gate arm is moved to the vertical position by gravity.

10 Claims, 5 Drawing Figures PATENTEBAPR 1 5 SHEET 1 OF 2 GRAVITYOPERATED ELECTROMAGNETICALLY CONTROLLED GATE BACKGROUND OF THE INVENTIONAutomatically controlled gate assemblies are known in the prior art,particularly the gate assemblies used at railway crossings, the gateassemblies being complex in structure and operated by signals receivedby an advancing train.

More recently, gate assemblies have been used in automotive parking lotsand are raised once a parking receipt is removed from a dispensingmachine. Another variety of gate is that used in private parking lots,usually in conjunction with a coded card which is recognizedelectronically and actuates a mechanism permitting the gate to beraised.

In other instances. a gate is used for control of traffic on privateaccess roads. the gate being energized by a control mechanism located inthe security office normally positioned in close proximity to the accessroad.

Heretofore, gate assemblies have been constructed to operate in avariety of different ways, including an energizing circuit whichaffirmatively controls movement of the gate from the horizontal to thevertical position and from the vertical position to the horizontal. Thistype of arrangement is sometimes objectionable because of problemsassociated with a power failure or malfunction of the gate or itscontrol apparatus. For example, if a gate is positively driven throughits various positions, and is in the vertical position, a malfunction orloss of power results in the gate being maintained in a horizontalposition thus obstructing the controlled flow oftraffic. In high densitytraffic areas such as parking lots or private access roads, this isobjectionable.

Other gates have been designed and operated which are somewhat complexand require highly trained individuals in order to repair or to performroutine maintenance on the gate assemblies. Some of these structureshave been designed to operate on a gravity basis, that is, the gate ismoved from the vertical to the horizontal position by virtue ofacounterbalanced gate arm which is caused to rotate to the horizontalposition by gravity.

For examples of various gate structures and control assemblies,reference is made to US. Pat. No. 599.020 of Feb. I5, 1898; US. Pat. No.903.905 of Nov. 17, 1908; US. Pat. No. 1,601,783 of Oct. 5, I926; US.Pat. No. 1,663,040 of Mar. 20, I928 and US. Pat. No. 1,765,178 of June17, I930.

SUMMARY OF THE INVENTION The present invention relates to a gateassembly and more particularly to an improved gate assembly which iselectromagnetically controlled and gravity operated by a simpleandreliable assembly whose principal functional components are enclosedwithin a single housing. By the present invention, several of thedisadvantages of prior art gate assemblies have been overcome, theprincipal advantage of the present invention being the simplicity of thestructure and its effectiveness as a controllable gate assembly. Thus, acounterbalanced gate element is used which is rotated from thehorizontal to the vertical position by gravity, and driven from thevertical to the horizontal position by a motor, clutch and gearassembly. Thus, in the event of a power failure, the gate automaticallyraises to the vertical position and does not act as a trafficobstruction barrier.

Additionally, because of the simplicity of the structure it is possible,in the event of some mechanical malfunction, manually to raise the gateto the vertical position thus permitting flow of traffic.

The highly reliable and effective gate structure of the presentinvention is enclosed within a housing, thus making it ideal for outdooruse. Positioned within the housing are the major functional componentsof the gate assembly and its driving mechanism, the latter including amotor and clutch assembly, the output of the clutch being a gearassembly which effects rotation of a gate arm. Attached to rotate withinthe housing as the gate arm rotates is a follower arm which contacts abrake and shock absorber assembly as the gate is rotated from thehorizontal to the vertical position, and which is engaged by anelectromagnet to maintain the gate in the horizontal position. As thegate arm is rotated towards the horizontal position from a verticalposition, the follower actuates a switch which deenergizes the motor butmaintains an electromagnet energized to hold the follower arm and thusthe gate.

To raise the gate, the control circuit is de-energized which affectsrelease of the electromagnet and gravity causes the gate to rotate fromthe horizontal to the vertical position as described. The gate elementitself includes a channel member mounted to be rotated by the driveshaft which is affixed to the gear assembly, the channel member carryinga gate arm which is at an angular orientation with respect to thechannel member, the channel member being counterbalanced such that thecounterweight tends to rotate the gate towards the vertical positionfrom a horizontal position. The present invention can best be understoodby reference to the following description taken in connection with theaccompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of thegate assembly of the present invention;

FIG. 2 is a view partly in section and partly in elevation of theinterior components of the gate assembly in accordance with the presentinvention;

FIG. 3 is a view, partly in section and partly in elevation of the shockabsorber assembly in accordance with the present invention;

FIG. 4 is a view, in perspective, of the interior working components ofthe gate assembly in accordance with the present invention; and

FIG. 5 is a plan view which also shows the electrical control apparatusof the gate assembly in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings whichillustrate a preferred embodiment of the present invention, FIG. 1 showsthe gate assembly 10 which includes a lower support member and housing11 above which is received an upper housing member 12 such thatsubstantially all of the interior working mechanism of the gate assemblyis completely closed and protected from the outside environment.

Extending through the housing 12 is a drive shaft 15 on which is mounteda gate element 20 including a channel member 21 and a gate arm 22, thelatter affixed to the channel member 21. As illustrated, the channelmember 21 carries a weight 24 whose position may be adjusted by slidingit along the channel member and securing it in place a proper distancefrom the drive shaft so as to effect a change in the rate at which thegate arm rotates from the horizontal to the vertical position. Normally,the weight 24 is adjusted to overcome the inertia of the gate armallowing gravitational forces to raise the gate arm from the horizontalposition, indicated in phantom lines, to the vertical position. The rateof movement from the horizontal to the vertical position is controlledby the adjustment of the position of the counterbalance weight 24, asdescribed. Also mounted exteriorally of the housing 12 is a shockabsorber assembly 26 which is contacted by the underside of the gate arm22 as the latter is positively driven from the vertical position to thehorizontal position.

Referring to FIG. 3, the details of the shock absorber 26 are shown, theshock absorber including a hollow aluminum spindle 27 affixed on asupport member generally indicated 28, the interior of the spindleincluding a spring 29 on which is mounted a Teflon cup 30 the latterbeing slidable with respect to the spindle 27.

Referring to FIGS. 2 and 4, the interior working components of the gateassembly include a motor mounted on a platform 36 supported between theframe members 37 and 38, the latter attached to the vertically extendingframe members 39 which are affixed to a suitable base which may be awood or concrete foundation. The output shaft 42 of the motor isconnected to an electromagnetic clutch assembly 45 through a coupling 46to a small spur gear 47. By way ofexample, the motor 35 and associatedspeed reducer may be of 1 15 volt, 30 amp, 60 cycle, l/th hp motoroperating at I725 rpm. The torque generated is 32 lb. in. The clutchassembly 45 may be of a type which is a rated 9 watt dc. voltagecontrolled clutch having a torque of 43 lb. in.

As illustrated in FIGS. 2 and 4, the output shaft 49 of the coupling 46is supported by a vertically extending frame member 50 cooperating witha vertically extending frame member 52 such that the spur gear 47 isheld in fixed alignment with a larger spur gear 55 positioned verticallybelow it and supported between the frame members 50 and 52. The spurgear 55 is splined to the drive shaft 15 on which the gate element 20 ismounted.

Interiorally of the housing there is also mounted on the drive shaft afollower arm which rotates with the drive shaft 15 and the gate arm. Asillustrated in FIG. 4, the follower arm 60 carries a steel plate 63 anda brake shoe 64, the steel plate cooperating with an electromagnet 65supported on the underside of the platform 36.

Supported beneath the lower frame member 38 is a second shock absorber68 of a structure identical to that already described in connection withFIG. 3. Mounted on another transverse support member 69 is a brake shoe70 which cooperates with the brake shoe 64 carried by the follower arm60.

The brake shoe 70 is relatively simple in structure and is in the formofa brush with stiff bristles cooperating with the brake shoe 64 carriedby the follower arm 60. Thus, as the gate arm moves from the horizontalto the vertical position, the brake shoe 64 comes in contact with thebrake shoe 70, and the follower arm contacts the shock absorber 68 toretard the movement of the gate arm from the horizontal to the vertical.Such a feature of the present invention is of practical importance inview of the fact that movement of the gate arm from the horizontal tothe vertical is-by gravitational force rather than through a positivedrive through the motor and clutch assembly.

The gate arm will remain in the vertical or up position for as long asthe circuit is not actuated. Upon actuation of the circuit, the motor isenergized and the gate is positively driven from the vertical to thehorizontal position.

As the follower arm 60 rotates with the gate arm, the plate 63cooperates with an electromagnet 65 to maintain the gate in thehorizontal position. As the follower arm 60 rotates to the horizontalposition, the plate also contacts a microswitch 72 which functions todeenergize the motor and clutch assembly while main taining theelectromagnet 65 energized to hold the gate in the horizontal position.As can be understood, the amount of electrical energy necessary tomaintain the electromagnet energized is rather minimal, and accordingly,an effective means is provided for maintaining the gate in a horizontalposition. In the event of a mechanical failure or electrical failure,the gate can be raised to the vertical position manually.

In movement of the gate arm from the vertical to the horizontalposition, the underside of the gate arm contacts the shock absorber 26so as to reduce any bouncing movement as the gate approaches thehorizontal position thus enabling the electromagnet 65 to hold the plate63 and the follower arm and the gate arm in a generally horizontalposition.

Referring to FIG. 5 wherein like reference numerals have been used whereapplicable, electrical power is supplied through any a.c. source 75, theelectrical circuit being controlled by a switch 76 which is illustratedas a manually operated switch. It is to be understood, however, thatswitch 76 may be operated by a ticket dispensing machine or by a cardrecognition circuit, in a manner well known to those skilled in the art.

The circuit includes a dc. converter 78 used to provide the dc. powerfor the electromagnetic clutch 45. Cooperating with the motor 35 is astarting capacitor 79 which functions in the usual manner of capacitancestarted motors. As illustrated, relay 72 is interconnected between themotor and the electromagnet 65 so as to maintain the electromagnetenergized while deenergizing the motor upon actuation of the relay 72 bythe plate 63 carried on the follower 60.

To illustrate the simplicity of the gate assembly of the presentinvention, the motor may be of the Bodine type N-lRG" gear motor. Theclutch assembly 45 may be of a Stearns style MSR electromagnetic clutchwhile the coupling 46 is a /2 in. X V2 in. FCS coupling. Gear 47 is a lin. diameter spur gear while gear 55 is a 9 in. diameter spur gear. Theelectromagnet 65 includes a dc. rectifier as part of its structure, theelectromagnet being interconnected to the dc. converter 78 asillustrated in FIG. 5.

The gate arm is preferably of wood, metal or plastic. and mounted on thechannel member 21. As illustrated in FIG. I, the gate arm 22 is offsetapproximately 10 with respect to the channel member 21 such that withthe gate in the horizontal position, the channel member is offset in thedirection of pivotal or rotational movement of the gate element. In thisway, the weight 24 is positioned above the horizontal arrangement of thegate arm. and once the electromagnet is de-energized by de-energizingthe circuit, gravitational forces act immediately to raise the gate fromthe horizontal to the vertical position. The angular disposition of thechannel member with the gate arm thus assists in overcoming the inertiatending to maintain the gate arm in the horizontal position.

As will be apparent to those skilled in the art. the rate at which thegate moves from the horizontal to the vertical position may be adjustedby sliding adjustment of the weight 24 within the channel member 21.

One of the features of the present invention is the function of theshock assemblies 26 and 68 which in addition to absorbing the shock ofmovement of the follower arm also operates to provide an initialmovement of the gate arm as it moves from the horizontal to the verticalposition and as it moves from the vertical to the horizontal position.This is apparent by virtue of the spring member which is compressedslightly once the respective shock members are contacted either by thegate arm or by the follower arm.

it will be apparent to those skilled in the art that various changes andmodifications may be made with respect to the structure herein describedwithout departing from the scope of the invention as set forth in theappended claims.

I claim:

1. An electromechanically controlled, gravity operated gate assemblycomprising:

an enclosed housing containing an electromechanical assembly foreffecting movement of a gate arm positioned externally of said housing,

gear means contained within said housing and connected to a drive shaftwhich extends through said housing,

a gate element mounted on the extending portion of said drive shaft.

said gate element including a counterbalanced channel member affixed formovement with said drive shaft and a gate arm secured to said channelmemher.

a motor and clutch assembly supported within said housing and connectedto drive said gear means,

a follower arm mounted within said housing for rotation with said shaft.

electromagnetic means supported within said housing and cooperating withsaid follower arm to maintain said gate in a generally horizontalposition,

switch means supported within said housing and engageable by saidfollower arm to maintain said electromagnet energized while said gatearm is in said horizontal position,

circuit control means operative in an energized state to activate saidmotor and clutch assembly for moving the gate arm from a verticalposition to a horizontal position.

said switch means being energized in response to contact by saidfollower arm to de-energize said motor and clutch assembly and tomaintain said electromagnetic means energized to maintain said gate armin said horizontal position, and

said circuit control means in the de-energized state being operative tode-energize said switch means whereby said gate arm is moved to thevertical position by gravity.

2. A gate assembly as set forth in claim 1 wherein said switch means ismounted such that said motor and clutch assembly is de-energized as saidfollower arm contacts said switch.

3. A gate assembly as set forth in claim 1 wherein a shock assembly ismounted within said housing to contact said follower as said gate arm israised to the vertical position.

4. A gate assembly as set forth in claim 1 wherein said gate arm isoffset about 10 with respect to said channel member such that with thegate arm in the horizontal position the channel member is offset in thedirection of pivotal movement of said gate ele ment.

5. A gate assembly as set forth in claim 1 wherein said channel memberis positioned at an angle above the vertical with the gate arm in thevertical position.

6. A gate assembly as set forth in claim 1 wherein a resilient shockmember is mounted outside of said housing for contact by said gate armas the latter approaches the horizontal position.

7. A gate assembly as set forth in claim 6 wherein said shock memberurges said gate arm from the horizontal position towards said verticalposition in response to de-energization of said electromagnet means.

8. A gate assembly as set forth in claim 3 further including frictionbrake means mounted within said housing and cooperating with saidfollower arm to slow movement of said gate arm as the latter approachesthe vertical position.

9. A gate assembly as set forth in claim 8 wherein a resilient shockmember is mounted outside of said housing for contact by said gate armas the latter approaches the horizontal position.

10. A gate assembly as set forth in claim 9 wherein said shock memberurges said gate arm from the horizontal position towards said verticalposition in response to de-en'ergization of said electromagnet

1. An electromechanically controlled, gravity operated gate assemblycomprising: an enclosed housing containing an electromechanical assemblyfor effecting movement of a gate arm positioned externally of saidhousing, gear means contained within said housing and connected to adrive shaft which extends through said housing, a gate element mountedon the extending portion of said drive shaft, said gate elementincluding a counterbalanced channel member affixed for movement withsaid drive shaft and a gate arm secured to said channel member, a motorand clutch assembly supported within said housing and connected to drivesaid gear means, a follower arm mounted within said housing for rotationwith said shaft, electromagnetic means supported within said housing andcooperating with said follower arm to maintain said gate in a generallyhorizontal position, switch means supported within said housing andengageable by said follower arm to maintain said electromagnet energizedwhile said gate arm is in said horizontal position, circuit controlmeans operative in an energized state to activate said motor and clutchassembly for moving the gate arm from a vertical position to ahorizontal position, said switch means being energized in response tocontact by said follower arm to de-energize said motor and clutchassembly and to maintain said electromagnetic means energized tomaintain said gate arm in said horizontal position, and said circuitcontrol means in the de-energized state being operative to de-energizesaid switch means whereby said gate arm is moved to the verticalposition by gravity.
 2. A gate assembly as set forth in claim 1 whereinsaid switch means is mounted such that said motor and clutch assembly isde-energized as said follower arm contacts said switch.
 3. A gateassembly as set forth in claim 1 wherein a shock assembly is mountedwithin said housing to contact said follower as said gate arm is raisedto the vertical position.
 4. A gate assembly as set forth in claim 1wherein said gate arm is offset about 10* with respect to said channelmember such that with the gate arm in the horizontal position thechannel member is offset in the direction of pivotal movement of saidgate element.
 5. A gate assembly as set forth in claim 1 wherein saidchannel member is positioned at an angle above the vertical with thegate arm in the vertical position.
 6. A gate assembly as set forth inclaim 1 wherein a resilient shock member is mounted outside of saidhousing for contact by said gate arm as the latter approaches thehorizontal position.
 7. A gate assembly as set forth in claim 6 whereinsaid shock member urges said gate arm from the horizontal positiontowards said vertical position in response to de-energization of saidelectromagnet means.
 8. A gate assembly as set forth in claim 3 furtherincluding friction brake means mounted within saiD housing andcooperating with said follower arm to slow movement of said gate arm asthe latter approaches the vertical position.
 9. A gate assembly as setforth in claim 8 wherein a resilient shock member is mounted outside ofsaid housing for contact by said gate arm as the latter approaches thehorizontal position.
 10. A gate assembly as set forth in claim 9 whereinsaid shock member urges said gate arm from the horizontal positiontowards said vertical position in response to de-energization of saidelectromagnet means.